/// Find uses of standard freeing functons on values allocated using devm_
/// functions. Values allocated using the devm_functions are freed when
/// the device is detached, and thus the use of the standard freeing
/// function would cause a double free.
/// See Documentation/driver-model/devres.txt for more information.
///
/// A difficulty of detecting this problem is that the standard freeing
/// function might be called from a different function than the one
/// containing the allocation function. It is thus necessary to make the
/// connection between the allocation function and the freeing function.
/// Here this is done using the specific argument text, which is prone to
/// false positives. There is no rule for the request_region and
/// request_mem_region variants because this heuristic seems to be a bit
/// less reliable in these cases.
///
// Confidence: Moderate
// Copyright: (C) 2011 Julia Lawall, INRIA/LIP6. GPLv2.
// Copyright: (C) 2011 Gilles Muller, INRIA/LiP6. GPLv2.
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options: --no-includes --include-headers
virtual org
virtual report
virtual context
@r depends on context || org || report@
expression x;
@@
(
x = devm_kmalloc(...)
|
x = devm_kvasprintf(...)
|
x = devm_kasprintf(...)
|
x = devm_kzalloc(...)
|
x = devm_kmalloc_array(...)
|
x = devm_kcalloc(...)
|
x = devm_kstrdup(...)
|
x = devm_kmemdup(...)
|
x = devm_get_free_pages(...)
|
x = devm_request_irq(...)
|
x = devm_ioremap(...)
|
x = devm_ioremap_nocache(...)
|
x = devm_ioport_map(...)
)
@pb@
expression r.x;
position p;
@@
(
* kfree@p(x)
|
* kzfree@p(x)
|
* __krealloc@p(x, ...)
|
* krealloc@p(x, ...)
|
* free_pages@p(x, ...)
|
* free_page@p(x)
|
* free_irq@p(x)
|
* iounmap@p(x)
|
* ioport_unmap@p(x)
)
@script:python depends on org@
p << pb.p;
@@
msg="WARNING: invalid free of devm_ allocated data"
coccilib.org.print_todo(p[0], msg)
@script:python depends on report@
p << pb.p;
@@
msg="WARNING: invalid free of devm_ allocated data"
coccilib.report.print_report(p[0], msg)
64'>diff
Age | Commit message (Expand) | Author | Files | Lines |
n' name='id' value='91539eb1fda2d530d3b268eef542c5414e54bf1a'/>
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the
following double-lock bug:
Double lock:
1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236;
2. call to function `pl330_release_channel' immediately after;
3. call to function `dma_pl330_rqcb' in line 1753;
4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505.
I have fixed it as suggested by Marek Szyprowski.
First, I have replaced `pch->lock' with `pl330->lock' in functions
`pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids
the double-lock by acquiring a different lock than `dma_pl330_rqcb'.
NOTE that, as a result, `pl330_free_chan_resources' executes
`list_splice_tail_init' on `pch->work_list' under lock `pl330->lock',
whereas in the rest of the code `pch->work_list' is protected by
`pch->lock'. I don't know if this may cause race conditions. Similarly
`pch->cyclic' is written by `pl330_alloc_chan_resources' under
`pl330->lock' but read by `pl330_tx_submit' under `pch->lock'.
Second, I have removed locking from `pl330_request_channel' and
`pl330_release_channel' functions. Function `pl330_request_channel' is
only called from `pl330_alloc_chan_resources', so the lock is already
held. Function `pl330_release_channel' is called from
`pl330_free_chan_resources', which already holds the lock, and from
`pl330_del'. Function `pl330_del' is called in an error path of
`pl330_probe' and at the end of `pl330_remove', but I assume that there
cannot be concurrent accesses to the protected data at those points.
Signed-off-by: Iago Abal <mail@iagoabal.eu>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>